Kaoruko is one of main characters in Sakura no Sono no Étoile and another main protagonist of Otoboku 2. She has a rough personality because her mother died in her infancy and her father brought up her all by himself. Her father operates consumer credit, her family had the misfortune of being broken up by borrowed money by the company, and she has held a grudge towards her classmates before entering Seio Girls' Academy.
Her onee-sama is Kana in the dormitory building. Kaoruko and Kana is called reverse sisters because she is 170 centimeters in height and Kana is short. She has a 3-dan in kendo and she is called Knight no Kimi after winning the fencing against an ace of fencing club; Kana's onee-sama Mizuho instructs her in fencing before the match.
She often losts in admiration of a beauty, and Chihaya's smile charms her at the first time in the dorm. She has complex for her femininity. She ask Chihaya instruct her in it. She knows Chihaya is a male because of Junichi's notice, but she supports Chihaya. She becomes the seventy-fifth elder sisters with Chihaya.